Materials Literature
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Abstract Interpenetrating polymer networks based on polyurethane and polyurethane ionomer were studied using wide‐angle and small‐angle X‐ray diffraction. The polyurethane network is a multiblock polymer based on the trimethylolpropane adduct with 2,4‐toluene‐diisocyanate and poly(propylene oxide tetrahydrofuran) copo…
A computer program has been developed for calculating the activity coefficients of aqueous silica species. This program allows to the testing of the saturation states of silicate minerals in solutions concentrated by evaporation, particularly in alkaline brines. This has been done first for water samples from the Lake…
Egg white (albumen) can be used to improve the foam characteristics of beers. Hydrolysis increases the foam potential of albumen to a level considerably superior to that of beer polypeptides and commercial whipping proteins from soy beans and also removes any tendency to cause hazes in pasteurized beer. It appears, ho…
Explication a partir de differentes discussions du mecanisme de durcissement par deformation lors de la formation des bandes de deformation, ces bandes etant reliees a la structure de dislocations et au systeme de glissement
A range of surface treatments including chromate and plasma etching, which are capable of producing both chemical modification and surface topography modification of polymer surfaces, were applied to polyetheretherketone. The resulting surfaces were characterized by X-ray photoelectron spectroscopy (XPS), scanning ele…
A single-crystal X-ray analysis of the salt [dbttf][SnEt2Cl3] has revealed that both the dibenzotetrathiafulvalenium radical cations, dbttf˙+, and the [SnEt2Cl3]– anions exist as dimers. The crystals are triclinic, space group P, with cell dimensions a= 12.795(3), b= 12.960(5), c= 7.463(1)Å, α= 95.86(3), β= 108.62(2),…
Par chauffage de melanges Cu 2 O-Ta 2 O 5 sous vide entre 800 et 1100 o C, preparation de deux phases intermediaires de compositions tres proches; Cu 5 Ta 11 O 30 et Cu 3 Ta 7 O 19 . Structures de ces phases
The Rietveld refinements of crystal structure were undertaken on powder samples of ZrO2 and HfO2 quenched from 600°C⋅6GPa. The results on orthorhombic ZrO2 were consistent with those of a single crystal obtained under pressure. The compressibility of this phase was calculated as 4.65×10-3GPa-1. The results on HfO2 wer…
Abstract A factorial experimental design determined separate and combined effects of MeCoB 12 (methylcobalamin) and Me 2 Co(N 4 ) + (a methylcobalamin model) on methylation of Sn(II) and Pb(II) in sediment matrices. Total methyltin yields ranged from 1.4% to 3.2%, and total methyllead yields varied from 0.037% to 0.11…
Unlike its metal-free precursor and NiII analogue, meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)- porphyrinatopalladium(II) undergoes very little aerial oxidation in basified dichloromethane, owing to metal-enforced planarity of the porphyrin macrocycle, as shown by crystal structure determinations of the two complexe…
Le comportement des électrons dans la matière est d'un intérêt fondamental, notamment en microscopie à balayage, en microanalyse et en physique spatiale. Nous présentons dans cet article l'ensemble de nos résultats expérimentaux dans le domaine de la diffusion multiple pour un faisceau d'électrons monocinétiques tomba…
Abstract Mechanical and rheo‐optical data have been obtained as a function of frequency at constant temperatures for two series of spherulitic and nonspherulitic samples of isotactic polypropylene having different ordering on molecular level. It was found that the structure differentation influence on the nature of th…
A radioisotope labeling technique was used to quantify the adherence of Staphy lococcus aureus, Staphylococcus epidermidis, and Escherichia coli on eight fabrics. The extent of bacterial adherence depends on the bacterial type, the fiber content, and the contact condition. Staphylococci adhered more than Escherichia c…
The optical reflectivity from the interfacial region of a nematic/solid wall boundary has been measured as a function of incident angle and temperature for 7CB. Considerable deviation from Fresnel reflectivity occurs for the E-ray whereas reflectivities for the 0-ray are similar to Fresnel. To fit the experimental dat…
Abstract Soils with firm, dense Bx horizons are extensive in the Upper Coastal Plains including the Sandhills of Georgia, North Carolina, and South Carolina. The Bx horizons are slightly brittle to brittle, but prisms with bleached, vertical faces are often weakly developed or absent. Three pedons of a series represen…
A number of esters of structure (I) incorporating the cyclobutane, spiro[3.3]heptane, or dispiro[3.1.3.1]decane rings has been prepared using a diethyl malonate synthesis. Strict comparison of the liquid crystal behaviour amongst the three classes containing a terminal cyano-substituent was not possible because both t…
Dans un sol, milieu heterogene, une racine peut rencontrer des zones de resistance differente a la pentration qui font obstacle a son enfoncement et a son developpement. En laboratoire, nous avons modelise un tel obstacle par une lamelle d'acier sur laquelle est collee une jauge extensometrique. Nous pouvons ainsi det…
Aqueous extract of Teucrium polium was broadly used in folk medicine for treatment of gastric ulcer in Iraq and some Arab countries. In our laboratory the induction of gastric ulcer was done in starved rats by reserpine (20 mg/kg i.p.) or by stress. T. polium (150 mg/kg i.p.) as a crude extract produced 50% healing of…
During growth of Escherichia coli on acetate, the glyoxylate bypass supplies the precursors needed for biosynthesis. The glyoxylate bypass enzyme isocitrate lyase competes with the citric acid cycle enzyme isocitrate dehydrogenase for the available isocitrate. We have studied the control of metabolic flux at this bran…
Several porous silicas have been studied in order to determine the origin of porosity in random porous media. The silica system offers a unique opportunity to study the origin of porous structures because a variety of different structures can be synthesized depending on precursor chemistry and physics. In solution‐gro…